Conception, synthèse et étude de nouveaux hétérocycles azotés d'intérêts biologiques  
An artificial photosynthetic system for photoaccumulation of two electrons on a fused dipyridophenazine (dppz) – pyridoquinolinone ligand  
[Full paper ]
Jean-François Lefebvre, Julian Schindler, Philipp Traber, Ying Zhang, Stephan Kupfer, Stefanie Grafe, Isabelle Baussanne, Martine Demeunynck, Jean-Marie Mouesca, Serge Gambarelli, Vincent Artero, Benjamin Dietzek, Murielle Chavarot-Kerlidou
Chem. Sci., 2018, 9, 4152-4159
Increasing the efficiency of molecular artificial photosynthetic systems is mandatory for the construction of functional devices for solar fuels production. Decoupling the light-induced charge separation steps from the catalytic process is a promising strategy, which can be achieved thanks to the introduction of suitable electron relay units performing charge accumulation. We report here on a novel ruthenium tris-diimine complex able to temporarily store two electrons on a fused dipyridophenazine-pyridoquinolinone -extended ligand upon visible-light irradiation in the presence of a sacrificial electron donor. Full characterization of this compound and of its singly- and doubly-reduced derivatives thanks to resonance Raman, EPR and DFT studies allowed to localize the two electron-storage sites and to relate charge photoaccumulation with proton-coupled electron transfer processes.